Phaseless Spherical Near-Field Antenna Measurements Using an Arbitrary Oriented Translation Axis

In phaseless Spherical Near-Field (SNF) measurements, the two-scans method is widely used. This technique relies on reconstructing the far-field radiation pattern of an Antenna Under Test (AUT) from amplitude measurements sampled over two spheres with different measurement radii. In an SNF setup, different radii can be achieved with a linear axis aligned to the AUT-probe path and translating either the AUT or probe. However, linear axes can also be used, which are not on an axis between AUT and probe. This is the case, for example, with axes for averaging the quiet zone influence in a hybrid test range combining a compact antenna test range and an SNF setup. Also in this case, the two-scans method can be applied by compensating the misalignment of AUT and probe through different rotations. This paper shows how the linear arbitrary oriented axis can be used for the two-scans method and describes the additionally required post-processing steps.